##// END OF EJS Templates
implab » implabjs-djx
RSS
added observable subject producer
added observable subject producer
cin - - Load All Authors

File last commit:

r125:cede47727a1b v1.7.0 default
r125:cede47727a1b v1.7.0 default
Show More
observable.ts
482 lines | 15.0 KiB | video/mp2t | TypeScriptLexer
/ djx / src / main / ts / observable.ts
History | Source | Raw |Copy content |Copy permalink
cin
added reduce() and next() methods to observable...
 r116 import { Cancellation } from "@implab/core-amd/Cancellation";
import { ICancellation } from "@implab/core-amd/interfaces";
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 /**
* The interface for the consumer of an observable sequence
*/
export interface Observer<T> {
/**
* Called for the next element in the sequence
*/
next: (value: T) => void;
cin
refactoring, adding scope to rendering methods
 r96
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 /**
* Called once when the error occurs in the sequence.
*/
cin
refactoring, adding scope to rendering methods
 r96 error: (e: unknown) => void;
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102
/**
* Called once at the end of the sequence.
*/
cin
refactoring, adding scope to rendering methods
 r96 complete: () => void;
}
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 /**
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 * The group of functions to feed an observable. These methods are provided to
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 * the producer to generate a stream of events.
*/
export type Sink<T> = {
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 /**
* Call to send the next element in the sequence
*/
cin
added reduce() and next() methods to observable...
 r116 next: (value: T) => void;
/**
* Call to notify about the error occurred in the sequence.
*/
error: (e: unknown) => void;
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
added reduce() and next() methods to observable...
 r116 /**
* Call to signal the end of the sequence.
*/
complete: () => void;
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
added reduce() and next() methods to observable...
 r116 /**
* Checks whether the sink is accepting new elements. It's safe to
* send elements to the closed sink.
*/
isClosed: () => boolean;
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 };
cin
refactoring, adding scope to rendering methods
 r96
export type Producer<T> = (sink: Sink<T>) => (void | (() => void));
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 export interface Unsubscribable {
unsubscribe(): void;
}
cin
added whenRendered() method to wait for pending oprations to complete
 r118 export const isUnsubscribable = (v: unknown): v is Unsubscribable =>
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 v !== null && v !== undefined && typeof (v as Unsubscribable).unsubscribe === "function";
cin
added whenRendered() method to wait for pending oprations to complete
 r118 export const isSubscribable = <T = unknown>(v: unknown): v is Subscribable<T> =>
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 v !== null && v !== undefined && typeof (v as Subscribable<unknown>).subscribe === "function";
cin
refactoring, adding scope to rendering methods
 r96
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 export interface Subscribable<T> {
subscribe(consumer: Partial<Observer<T>>): Unsubscribable;
}
cin
added reduce() and next() methods to observable...
 r116 export type AccumulatorFn<T, A> = (acc: A, value: T) => A;
cin
added while, until methods to the observable interface....
 r124 export type OperatorFn<T, U> = (source: Observable<T>) => Producer<U>;
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 /** The observable source of items. */
export interface Observable<T> extends Subscribable<T> {
/** Transforms elements of the sequence with the specified mapper
*
* @param mapper The mapper used to transform the values
*/
map<T2>(mapper: (value: T) => T2): Observable<T2>;
cin
refactoring, adding scope to rendering methods
 r96
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 /** Filters elements of the sequence. The resulting sequence will
* contain only elements which match the specified predicate.
*
* @param predicate The filter predicate.
*/
filter(predicate: (value: T) => boolean): Observable<T>;
cin
refactoring, adding scope to rendering methods
 r96
cin
added while, until methods to the observable interface....
 r124 /** Completes the sequence once the condition is met.
* @param predicate The condition which should be met to complete the sequence
*/
until(predicate: (value: T) => boolean): Observable<T>;
/** Keeps the sequence running while elements satisfy the condition.
*
* @param predicate The condition which should be met to continue.
*/
while(predicate: (value: T) => boolean): Observable<T>;
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 /** Applies accumulator to each value in the sequence and
* emits the accumulated value for each source element
*
* @param accumulator
* @param initial
*/
cin
added reduce() and next() methods to observable...
 r116 scan<A>(accumulator: AccumulatorFn<T, A>, initial: A): Observable<A>;
scan(accumulator: AccumulatorFn<T, T>): Observable<T>;
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
added reduce() and next() methods to observable...
 r116 /** Applies accumulator to each value in the sequence and
* emits the accumulated value at the end of the sequence
*
* @param accumulator
* @param initial
*/
reduce<A>(accumulator: AccumulatorFn<T, A>, initial: A): Observable<A>;
reduce(accumulator: AccumulatorFn<T, T>): Observable<T>;
/** Concatenates the specified sequences with this observable
*
* @param seq sequences to concatenate with the current observable
cin
added while, until methods to the observable interface....
 r124 *
* The concatenation doesn't accumulate values from the specified sequences,
* The result of the concatenation is the new observable which will switch
* to the next observable after the previous one completes. Values emitted
* before the next observable being active are lost.
cin
added reduce() and next() methods to observable...
 r116 */
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 cat(...seq: Subscribable<T>[]): Observable<T>;
cin
added pipe method to observable
 r114
cin
added while, until methods to the observable interface....
 r124
cin
added reduce() and next() methods to observable...
 r116 /** Pipes the specified operator to produce the new observable
cin
added while, until methods to the observable interface....
 r124 * @param op The operator consumes this observable and produces a new one
*
* The operator is a higher order function which takes a source observable
* and returns a producer for the new observable.
*
* This function can be used to create a complex mapping between source and
* resulting observables. The operator may have a state (or a side effect)
* and can be connected to multiple observables.
cin
added reduce() and next() methods to observable...
 r116 */
cin
added while, until methods to the observable interface....
 r124 pipe<U>(op: OperatorFn<T, U>): Observable<U>;
cin
added reduce() and next() methods to observable...
 r116
/** Waits for the next event to occur and returns a promise for the next value
* @param ct Cancellation token to
*/
next(ct?: ICancellation): Promise<T>;
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 }
const noop = () => { };
const sink = <T>(consumer: Partial<Observer<T>>) => {
const { next, error, complete } = consumer;
cin
refactoring, adding scope to rendering methods
 r96 return {
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 next: next ? next.bind(consumer) : noop,
error: error ? error.bind(consumer) : noop,
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 complete: complete ? complete.bind(consumer) : noop,
isClosed: () => false
cin
linting
 r109 };
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 };
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 /** Wraps the producer to handle tear down logic and subscription management
*
* @param producer The producer to wrap
* @returns The wrapper producer
*/
const fuse = <T>(producer: Producer<T>) => ({ next, error, complete }: Sink<T>) => {
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 let done = false;
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 let cleanup = noop;
const _fin = <A extends unknown[]>(fn: (...args: A) => void) =>
(...args: A) => done ?
void (0) :
(done = true, cleanup(), fn(...args));
cin
added while, until methods to the observable interface....
 r124 const _fin0 = () => done ? void (0) : (done = true, cleanup());
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 const safeSink = {
cin
linting
 r109 next: (value: T) => { !done && next(value); },
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 error: _fin(error),
complete: _fin(complete),
isClosed: () => done
cin
linting
 r109 };
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 cleanup = producer(safeSink) ?? noop;
cin
added while, until methods to the observable interface....
 r124 return done ? cleanup() : _fin0;
cin
linting
 r109 };
cin
refactoring, adding scope to rendering methods
 r96
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 const _observe = <T>(producer: Producer<T>): Observable<T> => ({
subscribe: (consumer: Partial<Observer<T>>) => ({
unsubscribe: producer(sink(consumer)) ?? noop
}),
cin
added reduce() and next() methods to observable...
 r116
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 map: (mapper) => _observe(({ next, ...rest }) =>
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 producer({
next: next !== noop ? (v: T) => next(mapper(v)) : noop,
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 ...rest
})
),
cin
added reduce() and next() methods to observable...
 r116
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 filter: (predicate) => _observe(({ next, ...rest }) =>
producer({
next: next !== noop ? (v: T) => predicate(v) ? next(v) : void (0) : noop,
...rest
cin
`Subscribable` is made compatible with rxjs, added map, filter and scan...
 r102 })
),
cin
added reduce() and next() methods to observable...
 r116
cin
added while, until methods to the observable interface....
 r124 until: predicate => _observe(({ next, complete, ...rest }) =>
producer({
next: v => predicate(v) ? complete() : next(v),
complete,
...rest
})
),
while: predicate => _observe(({ next, complete, ...rest }) =>
producer({
next: v => predicate(v) ? next(v) : complete(),
complete,
...rest
})
),
cin
added reduce() and next() methods to observable...
 r116 scan: <A>(...args: [AccumulatorFn<T, A>, A] | [AccumulatorFn<T, T>]) => _observe<T | A>(({ next, ...rest }) => {
if (args.length === 1) {
const [accumulator] = args;
let _acc: T;
let index = 0;
return producer({
next: next !== noop ? (v: T) => next(index++ === 0 ? _acc = v : _acc = accumulator(_acc, v)) : noop,
...rest
});
} else {
const [accumulator, initial] = args;
let _acc = initial;
return producer({
next: next !== noop ? (v: T) => next(_acc = accumulator(_acc, v)) : noop,
...rest
});
}
}),
reduce: <A>(...args: [AccumulatorFn<T, A>, A] | [AccumulatorFn<T, T>]) => _observe<T | A>(({ next, complete, error, ...rest }) => {
if (args.length === 1) {
const [accumulator] = args;
let _acc: T;
let index = 0;
return producer({
next: next !== noop ? (v: T) => {
_acc = index++ === 0 ? v : accumulator(_acc, v);
} : noop,
complete: () => {
if (index === 0) {
error(new Error("The sequence can't be empty"));
} else {
next(_acc);
complete();
}
},
error,
...rest
});
} else {
const [accumulator, initial] = args;
let _acc = initial;
return producer({
next: next !== noop ? (v: T) => {
_acc = accumulator(_acc, v);
} : noop,
complete: () => {
next(_acc);
complete();
},
error,
...rest
});
}
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110 }),
cat: (...seq) => _observe(({ next, complete: final, ...rest }) => {
let cleanup: () => void;
const complete = () => {
const continuation = seq.shift();
if (continuation) {
// if we have a next sequence, subscribe to it
const subscription = continuation.subscribe({ next, complete, ...rest });
cleanup = subscription.unsubscribe.bind(subscription);
} else {
// otherwise notify the consumer about completion
final();
}
};
cleanup = producer({ next, complete, ...rest }) ?? noop;
return () => cleanup();
cin
added pipe method to observable
 r114 }),
cin
added reduce() and next() methods to observable...
 r116 pipe: <U>(op: (source: Observable<T>) => Producer<U>) => observe(op(_observe(producer))),
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
added reduce() and next() methods to observable...
 r116 next: (ct?: ICancellation) => {
const _ct = ct ?? Cancellation.none;
return new Promise<T>((resolve, reject) => {
// wrap the producer to handle only single event
const once = fuse<T>(({ next, complete, error, isClosed }) => {
const h = _ct.register(error);
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
added reduce() and next() methods to observable...
 r116 // is the _ct fires it will call error() and isClosed() will return true
const cleanup = !isClosed() ?
producer({
next: v => (next(v), complete()),
complete: () => error(new Error("The sequence is empty")),
error,
isClosed
}) ?? noop :
noop;
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
added reduce() and next() methods to observable...
 r116 return () => {
h.destroy();
cleanup();
};
});
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
added reduce() and next() methods to observable...
 r116 once({
next: resolve,
error: reject,
complete: noop,
isClosed: () => false
});
});
}
});
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
export const observe = <T>(producer: Producer<T>) => _observe(fuse(producer));
cin
added reduce() and next() methods to observable...
 r116 export const streamArray = <T>(items: T[]) => _observe<T>(
({ next, complete }) => (
items.forEach(next),
complete()
)
);
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
added reduce() and next() methods to observable...
 r116 export const streamPromise = <T>(promise: PromiseLike<T>) => observe<T>(
cin
added while, until methods to the observable interface....
 r124 ({ next, error, complete }) => void promise.then(
v => (next(v), complete()),
error
)
cin
added reduce() and next() methods to observable...
 r116 );
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
added reduce() and next() methods to observable...
 r116 export const of = <T>(...items: T[]) => _observe<T>(
({ next, complete }) => (
items.forEach(next),
complete()
)
);
cin
corrected tear down logic handling in observables. Added support for observable query results
 r110
cin
added while, until methods to the observable interface....
 r124 export const empty = _observe<never>(({ complete }) => complete());
/**
* Creates a mutable state and the observable for the stored value.
*
* @param value The initial value for the state
* @returns an array of three elements `[observable, setter, getter]`
*
* The returned observable keeps the actual value and will emit it as the next
* element each time a consumer subscribes the observable.
*
* Calling the setter will update the stored value in the observable and notify
* all consumers.
*/
export const stateful = <T>(producer: Producer<T>): Producer<T> => {
const fusedProducer = fuse(producer);
type Status = "active" | "complete" | "error";
let lastValue: T;
let hasValue = false;
let status: Status = "active";
let lastError: unknown;
let subscribers: Sink<T>[] = [];
const sink: Sink<T> = {
isClosed: () => status !== "active",
complete: () => {
if (status === "active") {
status = "complete";
const _subscribers = subscribers;
subscribers = [];
_subscribers.forEach(s => s.complete());
}
},
error: e => {
if (status === "active") {
status = "error";
lastError = e;
const _subscribers = subscribers;
subscribers = [];
_subscribers.forEach(s => s.error(e));
}
},
next: v => {
if (status === "active") {
hasValue = true;
lastValue = v;
const _subscribers = subscribers;
_subscribers.forEach(s => s.next(v));
}
}
};
fusedProducer(sink);
return (s: Sink<T>) => {
const _subscribers = subscribers;
switch (status) {
case "active":
if (hasValue)
s.next(lastValue); // if hasValue is true,
cin
added observable subject producer
 r125 // lastValue has a valid value
cin
added while, until methods to the observable interface....
 r124 subscribers.push(s);
return () => {
if (_subscribers === subscribers) {
const pos = subscribers.indexOf(s);
if (pos >= 0)
subscribers.splice(pos, 1);
}
};
case "complete":
s.complete();
break;
case "error":
s.error(lastError);
break;
}
};
};
cin
added observable subject producer
 r125 /** Create the producer which will be called once when the first subscriber is
* attached, next subscribers would share the same producer. When all
* subscribers are removed the producer will be cleaned up.
*
* Use this wrapper to prevent spawning multiple producers.
*
* @param producer The source producer
* @returns The wrapped producer
*/
export const subject = <T>(producer: Producer<T>): Producer<T> => {
cin
added while, until methods to the observable interface....
 r124 const fusedProducer = fuse(producer);
cin
added observable subject producer
 r125 let subscribers: Sink<T>[] = [];
let cleanup = noop;
cin
added while, until methods to the observable interface....
 r124
cin
added observable subject producer
 r125 const sink: Sink<T> = {
isClosed: () => false,
complete: () => {
const _subscribers = subscribers;
subscribers = [];
_subscribers.forEach(s => s.complete());
cleanup();
},
error: e => {
const _subscribers = subscribers;
subscribers = [];
_subscribers.forEach(s => s.error(e));
cleanup();
},
next: v => {
const _subscribers = subscribers;
_subscribers.forEach(s => s.next(v));
}
};
return client => {
const _subscribers = subscribers;
subscribers.push(client);
if (subscribers.length === 1)
cleanup = fusedProducer(sink) ?? noop;
return () => {
if (_subscribers === subscribers) {
const pos = subscribers.indexOf(client);
if (pos >= 0)
subscribers.splice(pos,1);
if (!subscribers.length)
cleanup();
}
};
cin
added while, until methods to the observable interface....
 r124 };
};